JP6051916B2 - Nonlinear compensation apparatus, method, and transmitter - Google Patents

Description

  The following embodiments relate to the field of optical communication, and more particularly, to an intra-channel nonlinear compensation apparatus, method, and transmitter.

  In-channel nonlinearity is an inherent damage in optical transmission systems and is derived from the Kerr effect of optical fibers. When the single channel speed reaches 40 to 60 Gbits / s or more, pulses in the same channel spread very greatly due to the action of chromatic dispersion, overlap each other, and exchange energy between pulses overlapped by a nonlinear action. Occurs. In such a case, even if the receiving end compensates for residual chromatic dispersion in the transmission line (link), the system still suffers significant nonlinear damage. Effects on non-channel non-linear systems include timing jitter, signal amplitude fluctuations and ghost pulse generation.

  In recent years, with the further improvement of optical fiber transmission system capacity, more complex multidimensional modulation techniques have gradually replaced simple intensity modulation schemes and have become the focus of research. In order to be able to ensure that a complex modulation scheme has a sufficient signal-to-noise ratio, the link system needs to have higher input optical power, which is definitely a non-linear compensation of the system. Leads to an increase.

  For long-distance optical communication systems, how to compensate or reduce the compensation of intra-channel nonlinearity is an important research issue. People studied from the aspects of transmission line design, receiver DSP processing and transmission signal encoding. In the prior art, a method for reducing nonlinearity by subtracting nonlinear perturbation at the transmitter end has already been proposed. The method is based on one-time oversampling, where the perturbation term is equal to the weighted sum of the product of a series of three terms (symbol information data at three times), the weight values being the chromatic dispersion, gain / attenuation and nonlinearity of the transmission line. Determined by the coefficient. The advantage of this method is reduced complexity, especially in PSK systems, the precompensation waveform can be fully realized by the subtraction method.

  However, in the process of realizing the present invention, the inventor has shown that the hardware complexity of the current precompensation method is mainly due to the complexity of complex addition and the number of complex addition in the phase modulation system. Thus, it has been found that when the residual chromatic dispersion of the transmission line (link) is large, the number of pulse action terms increases in order to obtain a better compensation effect, so that the requirement for hardware becomes severe.

  The following is a list of documents useful for understanding the present invention and the prior art, which are incorporated herein by reference and are equivalent to those fully disclosed herein.

IEEE PTL Vol. 12, No. 4, 2000, Antonio Mecozzi et. Al., L. Dou, Z. Tao, L. Li, W. Yan, T. Tanimura, T. Hoshida, and JC Rasmussen, “A low complexity pre-distortion method for intra-channel nonlinearity,” in Proc. OFC / NFOEC2011 Conf ., Los Angeles, USA, March. 2011, paper OThF5.

  The present embodiment provides a nonlinear compensation apparatus, method, and transmitter, and combines a pulse action term based on the characteristics of the weighting coefficient, further reduces the computational complexity, and relaxes the requirement for hardware. .

  According to one aspect of the present embodiment, a non-linear compensation device is provided, and the device acquires in advance an information sequence acquisition unit for acquiring a symbol information sequence of a pulse signal input at a transmission end. A perturbation amount acquisition unit for calculating a weighted sum of pulse interaction terms at one or more times with respect to the current time by using a weighting coefficient corresponding to each term to acquire a perturbation amount generated in a transmission path of a certain length. A perturbation amount processor that combines the perturbation amount terms based on the weighting coefficients and converts the addition of complex numbers into a combination of addition and multiplication of symbols in a finite symbol set, and perturbations that have been processed with the symbol information sequence The signal is calculated based on the compensated symbol information sequence by calculating the difference with the amount and obtaining the compensated symbol information sequence. Including information compensator, for.

  According to another aspect of the present embodiment, a non-linear compensation method is provided. The non-linear compensation method acquires a symbol information sequence of a pulse signal input at a transmitting end, and stores each symbol in advance. By calculating a weighted sum of pulse interaction terms at one or more times with respect to the current time by using a corresponding weighting factor, a perturbation amount generated in a transmission path of a certain length is obtained, and the perturbation amount is based on the weighting factor The symbol information after compensation is calculated by converting the addition of complex numbers into a combination of addition and multiplication of symbols in a finite symbol set, and calculating the difference between the symbol information sequence and the perturbation amount processed. Obtaining a sequence and causing the transmitting end to transmit a signal based on the compensated symbol information sequence.

  According to another aspect of the present embodiment, a transmitter including the nonlinear compensator is provided, and the transmitter further performs pulse shaping based on a compensated symbol information sequence acquired by the nonlinear compensator. A pulse shaper for acquiring the waveform of each pulse; and a signal transmitter for receiving the waveform of each pulse transmitted by the pulse shaper and transmitting the waveform after modulating the waveform.

  The beneficial effect of the present embodiment is that the symbol information of the pulse signal input at the transmission end can be compensated. When the apparatus is applied to a transmitter, the transmitter uses the symbol information after the compensation to perform a pulse. The shaping and modulation can be done and finally the signals can be transmitted, and after these signals are subjected to the nonlinear effects of the optical fiber transmission line, the desired lossless signal can be obtained at the receiver.

  In addition, by combining the pulse action terms according to the characteristics of the weighting factor and converting the addition of complex numbers into a combination of addition and multiplication of symbols in a finite symbol set, the computational complexity is further reduced and the hardware requirements are reduced. Can be relaxed.

  With reference to the following description and drawings, this embodiment has been disclosed in detail, and a scheme in which the present invention can be employed has been clarified. It should be understood that this embodiment is not thereby limited in scope. Within the spirit and scope of the appended claims, this embodiment includes many changes, modifications and equivalents.

  Descriptions of embodiments and / or features shown may be used in one or more other implementations in the same or similar manner, combined with features in other implementations, or substituted for features in other implementations can do.

  The term “include / include” (include / include) as used herein refers to the presence of a feature, the entire article, step or assembly, but the presence or absence of one or more other features, the entire article or assembly, or It does not exclude the addition.

1 is a diagram illustrating a typical optical communication system. It is a figure which shows the structure of the nonlinear compensation apparatus of a present Example. It is one flowchart of the nonlinear compensation method of a present Example. It is another flowchart of the nonlinear compensation method of a present Example. It is a figure which shows the structure of the transmitting apparatus of a present Example.

  Next, each embodiment will be described based on the drawings. These embodiments are merely exemplary and are not a limitation on the present invention. In order that those skilled in the art can easily understand the present invention and the embodiments, the embodiments will be described by taking an optical communication system as an example. However, this embodiment can be applied to all communication systems in which nonlinear loss exists.

  FIG. 1 is a diagram showing a typical optical communication system in which a signal transmitted by a transmitter is transmitted to a receiver via various devices (optical fiber, optical amplifier, chromatic dispersion compensating optical fiber, etc.) in a transmission path. To reach. In this embodiment, the non-linear compensator compensates the symbol information sequence of the pulse signal input at the transmission end, causes the transmission end to transmit a signal with a specific modification, and these signals receive the nonlinear effect of optical fiber transmission. After that, the desired lossless signal can be obtained at the receiver.

  In the system shown in FIG. 1, in order to compensate the pulse signal input at the transmission end, in the process of performing the present invention, the inventor first constructs an intra-channel nonlinear model and then inputs the nonlinear model based on the nonlinear model. Compensated for the pulse signal.

  In the normal case, since the transmitter end uses the normal polarization multiplexing method so that the spectral efficiency can be maximized, the following is the process of obtaining the intra-channel nonlinear model using dual polarization as an example. Give an explanation.

First, for vector signals, the transmission optical fiber can be modeled as a Manakov equation as shown in equation (1).

In the equation, u _H (t, z) and u _V (t, z) are electric field components (components) in the horizontal H and vertical V-direction polarization states of the signal, respectively, α (z), β ₂ (z). And γ (z) represent the distribution along the transmission distance of the attenuation coefficient, chromatic dispersion coefficient, and nonlinear coefficient in the optical fiber transmission line, respectively.

Next, since the signal generated from the transmitter is usually an optical pulse, the electric field component at the transmitter end can be expressed in the form of formula (2).

In the equation, A ^H _k and A ^V _k are signal symbols of the k-th pulse in the horizontal H and vertical V polarization states, respectively, T is a pulse interval, and g (t) is a waveform of each pulse. Here, even if the output signal of the transmitter is an optical signal having an arbitrary waveform, if the time interval T is set sufficiently small, the output optical signal can still be regarded as in the form of equation (2).

Finally, when the input signal (2) is substituted into the equation (1) and the transmission optical power is not so large (that is, the nonlinearity of the optical fiber transmission line is not so strong), the equation (1) is solved using perturbation theory, Equation (3) can be obtained.

  Here, in the equation (3), the electric field value at the receiver end Kth pulse sampling time is composed of the electric field value of the transmitting end Kth pulse and the perturbation amount, where the perturbation amount is a weighted sum of a plurality of interaction terms. Yes, each term is a transmission pulse information symbol product of one or more times. Here, in the process of solving equation (1) using the above perturbation theory, only the low order terms are handled and the high order terms are ignored.

  Therefore, it is only necessary to calculate the weighted sum of the pulse interactions at the three times with respect to the kth pulse sampling time, the m + k time, the n + k time, and the m + n + k time in the formula (3). However, when considering higher order terms in the process of finding a solution, it is necessary to calculate a weighted sum of pulse interactions at three or more times with respect to the Kth pulse sampling time.

  The three time pulses used for the kth pulse are not arbitrary, and the time relationship between them satisfies (m + k) + (n + k) − (m + n + k) = k. Where m, n and k may be the same, ie the pulse sampling time may be one or more times relative to the current time. It should be noted that the present embodiment is not limited to this, and the three pulses may further have other types of combinations, and the corresponding coefficients need to be appropriately modified.

  In the following description, the weighted sum of the interaction of all three pulses will be described as an example. The present invention is not limited to this, and the case of more than three pulses is similar to the case of three pulses.

As can be seen from Equation (3), the perturbation term in the current polarization state is derived from two parts, one part is derived from the present polarization state, and the other part is derived from the orthogonal polarization state. For example, for the horizontal polarization state, the portion derived from this polarization state is A ^H _{m + k} A ^H _{n + k} (A ^H _{m + n + k} ) ^* , and the portion derived from the orthogonal polarization state is A ^H _{m + k} A ^V _{n + k} (A ^V _{m + n +} ^k) is a ^*. The situation for the vertically polarized state is similar and will not be discussed further here.

  In the Masakov equation (1), since the symbol information of the two polarization states always appears symmetrical, the symmetry causes the coefficients of the perturbation terms in the two parts of the horizontal and vertical polarization states to be the same eventually. Become. The coefficient relates only to the arrangement of the transmission line and the relative position (m, n) of the interacting pulse with the pulse at the current time.

  Based on the non-linear model, signals having undergone specific deformation are transmitted at the transmitting end, and after these signals are subjected to the nonlinear effect of optical fiber transmission, a desired lossless signal can be obtained at the receiving end. Here, it can be assumed that the linear loss of the channel has already been compensated by other methods.

Furthermore, formula (3) can be rearranged to obtain the following formula (4) equivalently.

  As for the PSK signal, since the modulus of each symbol is the same, the factor multiplied by the current symbol information in the second term on the right side of the equal sign in equation (4) is a constant. Considering that the factor is an imaginary number, the effect seen at the receiving end is the rotation of the entire constellation. Since coherent receivers often have a phase recovery algorithm, the rotation is completely corrected.

Therefore, when actually considering the nonlinear effect, the effect of the term can be ignored, that is, the symbol information at the current time is discarded, and the last two additive perturbations of the right side of the equal sign of equation (4) Consider impact only. Thus, equation (4) can be further written as equation (5).

  For example, for other non-constant modulus modulation signals such as quadrature amplitude modulation (QAM) or orthogonal frequency division multiplexing (OFDM), if the accumulated chromatic dispersion of the transmission line is large, Since the number of acting pulses increases and the phase rotation of the non-linear pull-in is approximately the same due to the average effect, equation (5) still holds. In equation (5), only the additive strain of nonlinear entrainment was considered. For polarization multiplexed signals, this perturbation comes from the main polarization state and the orthogonal polarization state.

In the above description, a dual-polarized signal is described as an example. However, when a single-polarized signal is transmitted in a channel, Equation (5) can be further simplified as Equation (6). .

  C (m, n, z = L) corresponds to the weighting coefficient of the interaction of the mth, nth and m + n pulses with respect to the current time. Here, it is necessary to point out that in the polarization multiplexing system, the three interacting pulses may originate from the same polarization state or from different polarization states. The weighting coefficient corresponding to each term can be acquired in advance.

  Here, when the weighting coefficient is obtained based on a simulation and experiment method, different transmission signals can be designed in the simulation or experiment, and the value of the weighting coefficient is calculated backward based on the received signal. The above method is highly accurate.

ここで、現在時刻が第ｋ時刻である場合、現在時刻に対する３つの異なる時刻は第ｍ＋ｋ時刻、第ｎ＋ｋ時刻及び第ｍ＋ｎ＋ｋ時刻となる。所定の若干項の（ｍ，ｎ）値、各項の（ｍ，ｎ）値はいずれも異なる重み付け係数Ｃ（ｍ，ｎ，ｚ＝Ｌ）に対応する。ここで、ｍ及びｎの取る値は負の無限大から正の無限大までの間の任意の値を含んでよく、現在の第ｋ時刻の前、後の値すべてに関係する。 Here, when acquiring the weighting coefficient of each term based on the transmission line arrangement and the relative position between the pulse interacting at different times and the pulse at the current time, calculate the weighting coefficient using the following equation (7). Can do.

Here, when the current time is the kth time, three different times with respect to the current time are the m + k time, the n + k time, and the m + n + k time. The predetermined (m, n) value of some terms and the (m, n) value of each term all correspond to different weighting coefficients C (m, n, z = L). Here, the values taken by m and n may include any value between negative infinity and positive infinity, and relate to all values before and after the current k-th time.

  In general, as the absolute value of (m, n) increases, the corresponding absolute value of C (m, n, z = L) also decreases, and therefore, constant according to the required calculation accuracy. The perturbation amount can be calculated by taking the (m, n) value of the quantity.

  In this way, m and n can take values in the following manner. When m and n are handled, the modulus | C (m, n, z = L) | of the weighting coefficient C (m, n, z = L) obtained based on the m and n is a predetermined value or more. In this case, m and n may be used. Otherwise, m and n are not used. The predetermined value can be set by a proportional coefficient having a maximum modulus value of all coefficients. For example, the standardization coefficient C is | C (m, n, z = L) |> 1e−3 * max (| C ( All combinations of m and n that satisfy m, n, z = L) |) can be selected.

  Here, p (z) represents the power of a signal at a point Z away from the transmission end in the transmission line, s (z) represents a cumulative chromatic dispersion net value at a point Z away from the transmission end in the transmission line, and τ Represents the full width at half maximum of the pulse, T represents the pulse interval, and γ (z) represents the nonlinear coefficient at a point Z away from the transmission end in the transmission line.

Alternatively, when the transmission path does not include a chromatic dispersion compensation module, and at the same time ignores attenuation in the signal transmission process, and the chromatic dispersion coefficient and the nonlinear coefficient do not change with the transmission distance, the following equation (8) is used. The weighting factor can also be calculated.

と表すことができる。 In the equation, γ represents a nonlinear coefficient, p ₀ represents the power of the transmitting end signal, β ₂ represents a chromatic dispersion coefficient, exp int represents an exponential integral function, and the integral function is

It can be expressed as.

Further, the obtained weighting coefficient can be stored and used when calculating the weighting value. Channel parameters for calculating the weighting coefficient, for example, parameters such as nonlinear coefficient γ, chromatic dispersion coefficient β ₂ , and transmission path length L can be stored.

  The nonlinear precompensation model has a lower complexity than based on channel inversion and a nonlinear filter implemented at the receiver end. Here, since the distortion of the nonlinear pull-in is the sum of the interaction terms, and the multiplication between the information symbols in each term is obtained by a logical operation, the multiplication number necessary for pre-compensation is the number of terms in the interaction term. If the modulation scheme of the system is a phase modulation system (BPSK, QPSK, etc.), the multiplication between information symbols and coefficients is also obtained by a logical operation, and the precompensation method does not require any multiplication operation.

  Therefore, for a phase modulation system, the complexity of the precompensation hardware is mainly determined by the complexity of complex addition and the number of complex additions. Here, the number of complex additions is equal to the number of terms in the equation (5) or (6). When the residual chromatic dispersion of the transmission line is large, in order to obtain a better compensation effect, the number of terms in the equation (5) or (6) also increases, which leads to high computational complexity and The demands will also be severe.

  Based on the above analysis, the non-linear compensation apparatus, method, and transmitter of this embodiment will be described in detail below by taking the optical communication system shown in FIG. 1 and the non-linear model based on the communication system as an example.

  FIG. 2 is a diagram showing the configuration of the nonlinear compensator of this embodiment. As shown in FIG. 2, the nonlinear compensation device includes an information sequence acquisition unit 201, a perturbation amount acquisition unit 202, a perturbation amount processing unit 203, and an information compensator 204.

  Here, the information sequence acquisition unit 201 is used to acquire a symbol information sequence of the pulse signal input at the transmission end, and the perturbation amount acquisition unit 202 uses a weighting coefficient corresponding to each term acquired in advance. The perturbation amount processor 203 is used to calculate a weighted sum of pulse interaction terms at one or more times with respect to the current time to obtain a perturbation amount generated in a transmission line of a certain length. Combining the terms of the perturbation quantity, converting the addition of complex numbers into a combination of symbol addition and multiplication in a finite symbol set, the information compensator 204 calculates the difference between the symbol information sequence and the perturbation quantity after processing. In order to calculate and obtain a compensated symbol information sequence, and to cause the transmitting end to transmit a signal based on the compensated symbol information sequence It is needed.

  In the present embodiment, the symbol information sequence acquired by the information sequence acquisition unit 201 is symbol information before compensation. Here, the symbol information is related to the modulation scheme used, and the symbol information differs for different modulation schemes. For example, for an OOK modulation scheme, the symbol information sequence is 0, 1; for a BPSK modulation scheme, the symbol information sequence is −1, 1; for a QPSK modulation scheme, the symbol information sequence is 1 , J, −1, −j.

  In the present embodiment, the perturbation amount acquisition unit 202 can be used to calculate the perturbation amount for each transmission symbol (transmission time), and the perturbation amount is equal to the weighted sum of a plurality of interaction terms. An action term is a product between one or more different symbols.

  In this embodiment, the perturbation amount processor 203 specifically combines terms corresponding to the same or approximately the same weighting factor, or combines terms corresponding to the real part of the weighting factor, or weights. It can be used to combine terms corresponding to the imaginary part of the coefficients.

  Specifically, to further reduce the hardware complexity, the terms in equation (5) or (6) can be combined according to the characteristics of the coefficient C (m, n). When combining terms corresponding to the same or approximately the same C (m, n) or its real or imaginary part, use the addition of symbols in the finite symbol set to replace the original high-precision complex addition, One complex multiplication can be introduced at the same time.

  In this way, the number of complex additions in equation (5) or (6) can be significantly reduced, thereby reducing complexity. If the transmission data is QPSK, the product of the three QPSK symbols is still QPSK, and the addition of N QPSKs simultaneously calculates the number of 1s (or 0s) in the N binary numbers. The hardware complexity of such operations is much less than the addition of any arbitrary N complex numbers.

  In this embodiment, the information compensator 204 specifically subtracts the amount of perturbation acquired by the perturbation amount processor 203 using the symbol information sequence acquired by the information sequence acquisition unit 201 and compensates for the symbol after the current time is compensated. It can be used to obtain an information sequence.

  In a specific implementation, a corresponding hardware circuit may be used, or an adder, a multiplier, a logical operation circuit, or the like may be used. For example, for a PSK signal, multiplication between symbols can be realized using a look-up table, and multiplication between a PSK signal and Coef can be realized using a logical operation and an adder. When specifically implemented, conventional components can be used.

  In this embodiment, the perturbation amount acquisition unit 202 can acquire symbol information of one or more time pulses with respect to the current time of each term in a plurality of terms, and at one or more times with respect to the current time of each term. Using the symbol information of the pulse and the weighting coefficient corresponding to each term acquired in advance, the weight value of the interaction of the pulse at one or more times with respect to the current time in each term is calculated. Based on the weighting values, the sum of the weighting values of a plurality of terms is calculated to obtain the amount of perturbation that occurs in the transmission line of a certain length.

  Next, description will be made by taking as an example the calculation of the weighted sum of the interaction of the pulses at the three times with respect to the kth pulse sampling time, the m + k time, the n + k time, and the m + n + k time. Here, the number of terms used during the weighted sum calculation of the interaction of pulses at three times with respect to the current time of some terms is determined by a predetermined (m, n) value.

  Note that (m + k) + (n + k) − (m + n + k) = k is satisfied between m, n and k. Here, m, n, and k may be equal, that is, the pulse sampling time may be one or more times with respect to the current time.

  Further, in a specific embodiment, mn ≠ 0 may be expressed, which means that neither m nor n should be 0, whereby (m + k) and (n + k) may be equal, m + n + k), ie, the pulse sampling time may be at least two times relative to the current time.

  In this way, the perturbation amount acquisition unit 202 specifically calculates the weighted sum of the interaction of pulses at the current time, for example, three times with respect to the kth time, for example, the m + k, n + k, and m + n + k times, The k-th time nonlinear effect can be used to acquire the amount of perturbation that occurs through a transmission line having a certain length.

  The above is an example of how the perturbation amount acquisition unit 202 acquires the perturbation amount. Next, how the perturbation amount processor 203 combines terms will be described in detail through a single polarization signal and a dual polarization signal, respectively.

In this embodiment, since the coefficient C (m, n, z = L) itself is a complex number, each additive term in the equation (5) or the equation (6) is an arbitrary complex number. The coefficient C (m, n, z = L), for example, when m ^* n ≠ 0, the coefficient is related only to the product of m and n, and the symbol of m ^* n ≠ 0 and m ^* n is reversed. The imaginary part of the coefficient remains unchanged and the real part is reversed. When n = 0, the real part of the coefficient is much smaller than the imaginary part and can be ignored. In some cases, the coefficient may have properties such as being related only to the modulus value of m.

  It is worth noting that the above is merely an example illustrating the characteristics of the coefficient C (m, n, z = L), and is not limited thereto. Based on the other properties of the coefficients, the perturbation terms can be combined to convert the addition of complex numbers into a combination of symbol addition and multiplication in a finite symbol set. Depending on the specific embodiment, it can be determined.

Specifically, for a single polarization signal, the perturbation amount acquisition unit 202 can first calculate the sum of weighted values of a plurality of terms using the following equation.

In the equation, Δ _k represents the sum of the weight values of some terms at the k-th time, C (m, n, z = L) represents the weight coefficient of each term at the transmission line L point, and A _{m + k} and A _{n + k} are The symbol information of the pulse at the ( _{m + k} ) time and the ( _{n + k} ) time is represented, and (A _{m + n + k} ) ^* represents the conjugate of the symbol information of the pulse at the ( _{m + n + k} ) time.

Thereafter, the perturbation amount processor 203 can combine specific similar terms based on some or all of the characteristics of the coefficient C (m, n, z = L). For example, if m ^* n ≠ 0, based on the fact that the coefficient is only related to the product of m, n, the following equation is used when combining perturbation terms:

  Here, Re () in the above formula represents taking a real part, and Im () represents taking an imaginary part. Compared with equation (9), the double sum for m and n is changed to a single sum for the product a of m and n.

Alternatively, when m ^* n ≠ 0, the coefficient is related only to the product of m and n, and when the symbol of m ^* n ≠ 0 and m ^* n is reversed, the imaginary part of the coefficient remains unchanged. Based on that, the real part is reversed. When the perturbation amount processor 203 combines perturbation amount terms, the following equation is used.

Specifically, for a dual-polarized signal, the perturbation amount acquisition unit 202 can first calculate the sum of weighted values of a plurality of terms using the following equation.

Where Δ ^H _k and Δ ^V _k represent the sum of weighted values of the horizontal polarization state and the vertical polarization state of some terms at the k-th time, respectively, and C (m, n, z = L) is the transmission line It represents the weighting coefficient of each term at point L, A ^H _{m + k} and A ^V _{m + k} represent the symbol information of the pulse at the m + k time in the horizontal polarization state and the vertical polarization state, respectively, and A ^H _{n + k} and A ^V _{n + k} represent respectively The symbol information of the pulse at the ( _{n + k} ) _th time in the horizontal polarization state and the vertical polarization state is expressed, and (A ^H _{m + n + k} ) ^* and (A ^V _{m + n + k} ) ^* are the m + n + k time in the horizontal polarization state and the vertical polarization state, respectively. Represents conjugate of pulse symbol information.

Thereafter, the perturbation amount processor 203 can combine specific similar terms based on some or all of the characteristics of the coefficient C (m, n, z = L). For example, if m ^* n ≠ 0, the coefficient is only related to the product of m, n, and if n = 0, the real part of the coefficient is much smaller than the imaginary part and can be ignored. Based on the above characteristics, the following formula is used when combining the terms of the perturbation amount. In the formula, m and n are integers, and a = m × n and not 0.

Or, when m ^* n ≠ 0, the coefficient is related only to the product of m and n, and when m ^* n ≠ 0 and the symbol of m ^* n is reversed, the imaginary part of the coefficient remains unchanged. If the real part is reversed and n = 0, then the real part of the coefficient is much smaller than the imaginary part and can be ignored. If n = 0, the coefficient is only related to the modulus value of m. Based on the characteristic that the perturbation amount processor 203 combines the terms of the perturbation amount, the following equation is used.

  In the formula, m and n are integers, and a = m × n and not 0.

  In practical applications, it is further possible to quantize each real and imaginary part of the coefficients, thereby combining more terms and further reducing hardware complexity. That is, the perturbation amount processor 203 can also quantize the weighting coefficient before combining the terms corresponding to the weighting coefficient.

  When implemented concretely, it is possible to perform equal interval quantization on the weighting coefficient. For example, a numerical value of 0 to 1 is quantized to 1, a numerical value of 1 to 2 is quantized to 2, and a numerical value of 2 to 3 Can be defined to be quantized to 3 or the like. When the value of the coefficient C (m, n, z = L) is 2.6 + 1.3j, the numerical value after quantization is 3 + 2j. However, the present invention is not limited to this, and unequal interval quantization can be performed on the weighting coefficient. For example, a numerical value of 0 to 1 is quantized to 1 and a numerical value of 1 to 10 is quantized to 5 and exceeds 10. It can be specified that the numerical value is quantized to 10.

  It is worth noting that the above is only an example of quantization and has been described, and that specific embodiments can be determined according to the actual situation. The quantization is performed for each term of the weighting coefficient, and various quantization criteria can be used.

Specifically, when the input pulse signal is a single polarization signal, the perturbation amount processor 203 can use the following equation when combining the perturbation amount terms.

In the equation, Δ _k represents the sum of the weight values of some terms at the k-th time, C (m, n, z = L) represents the weight coefficient of each term separated from the L point, and Rp and Iq are respectively quantum Represents the real and imaginary parts of the coefficient C after conversion (mn ≠ 0, z = L), m and n are integers, p and q represent different quantization series, and A _{m + k} and A _{n + k} are respectively Symbol information of the pulse at the ( _{m + k} ) time and the ( _{n + k} ) time is represented, and (A _{m + n + k} ) ^* represents the conjugate of the symbol information of the pulse at the ( _{m + n + k} ) time.

When the input pulse signal is a dual polarization signal, the perturbation amount processor 203 can use the following equation when combining the perturbation amount terms.

In the equation, Δ ^H _k and Δ ^V _k represent the sum of weighted values of the horizontal polarization state and the vertical polarization state of some terms at each k-th time, and C (m, n, z = L) is L Represents the weighting coefficient of each term separated from the point, m and n are integers, Rp and Iq represent the real part and imaginary part of the quantized coefficient C (mn ≠ 0, z = L), respectively, and Ds Represents the imaginary part of the quantized coefficient C (m, n = 0, z = L), p, q, s represent different quantization series, and A ^H _{m + k} and A ^V _{m + k} are respectively horizontally polarized waves Represents the symbol information of the pulse at the (m + k) th time in the state and the vertical polarization state, and A ^H _{n + k} and A ^V _{n + k} represent the symbol information of the pulse at the (n + k) th time in the horizontal polarization state and the vertical polarization state, respectively (A ^H _{m + n +} ^{k) *} and _{^{(A V m + n + k}} ) * each horizontal Represents the conjugation of the symbol information of the pulses of the m + n + k time in the wave state and the vertical polarization state.

Here, the real part and the imaginary part of the coefficient C (m, n, z = L) where m ^* n ≠ 0 can be quantized with Rp and Iq, respectively, where p and q are different quantizations. Represents a series. For the coefficient C of n = 0 (m, n = 0, z = L), since the real part is much smaller than the imaginary part, it is only necessary to consider the contribution of the imaginary part, and the imaginary part is quantized as Ds. Where s represents a different quantization series.

  The above has described in detail how the perturbation amount processor 203 is specifically realized. It is worth noting that those skilled in the art can make appropriate modifications or transformations based on the contents disclosed above. The formula of this embodiment is only what was illustrated and is not restricted to this.

  In the present embodiment, the perturbation amount processor 203 is used to rotate the obtained perturbation amount by a predetermined phase, and the perturbation amount can be adjusted by a predetermined width coefficient. In the simulation, it was found that the system performance can be further improved effectively.

As a result, the information compensator 204 can use the following equation for a single polarization signal.

Wherein, xi] represents the width coefficient, theta represents the phase, also delta _k represents the perturbation quantity after the binding of the term.

For the dual polarization signal, the information compensator 204 can use the following equation.

In the equation, ξ represents the width coefficient, θ represents the phase, and Δ ^H _k and Δ ^V _k represent the amount of perturbation after combining the above terms. In general, the width factor ξ is a real number greater than 0 and less than 1, and the greater the nonlinearity of the system, the smaller the width factor ξ. It can be obtained by observing system performance such as the bit error rate at the receiver end.

  Through simulation, it is possible to reduce the addition of complex numbers by a factor of 100 after combining similar terms using quantization for the coefficients within the 1500km all-normal single-mode optical fiber transmission line, and at the same time the performance cost of the system is 0 It was verified that there was only .1 dB.

  As can be seen from the above embodiments, the nonlinear compensation device can compensate the symbol information of the pulse signal input at the transmission end, and when the device is applied to a transmitter, the transmitter can perform symbol information after the compensation. Can be used to perform pulse shaping and modulation, and finally transmit signals, and after these signals are subjected to the nonlinear effects of the optical fiber transmission line, the desired lossless signal can be obtained at the receiver.

  Also, depending on the characteristics of the weighting factor, the pulse action terms are combined, and complex addition is converted into a combination of symbol addition and multiplication within a finite symbol set, thereby further reducing the computational complexity and Requirements can be relaxed.

  This embodiment further provides a nonlinear compensation method. FIG. 3 is a flowchart of the nonlinear compensation method of this embodiment. The same contents as in the above embodiment are not described here.

  As shown in FIG. 3, the nonlinear compensation method includes a step 301 for acquiring a symbol information sequence of a pulse signal input at a transmitting end, and a weighting coefficient corresponding to each term acquired in advance, and 1 for the current time. Calculating a weighted sum of pulse interaction terms at two or more times to obtain a perturbation amount generated in a transmission line of a certain length; combining the perturbation amount terms based on a weighting factor; and adding a complex number Step 303 of converting into a combination of addition and multiplication of symbols in a finite symbol set, calculating a difference between perturbations after combining the symbol information sequence and the term, obtaining a compensated symbol information sequence, and transmitting Step 304 causes the end to transmit a signal based on the compensated symbol information sequence.

  Further, in step 303, the terms of the perturbation amount are combined based on the weighting coefficient, specifically, the terms corresponding to the same or approximately the same weighting coefficient are combined, or the terms corresponding to the real part of the weighting coefficient are combined. Combining or combining terms corresponding to the imaginary part of the weighting factor may be included.

In one embodiment, the input pulse signal is a dual polarization signal, and when the perturbation amount term is combined based on the weighting coefficient in step 303, specifically, the following equation is used.

Where Δ ^H _k and Δ ^V _k represent the sum of weighted values of the horizontal polarization state and the vertical polarization state of some terms at the k-th time, respectively, and C (m, n, z = L) is the transmission line Represents the weighting coefficient of each term at point L, m and n are integers, a = m × n and not 0, and A ^H _{m + k} and A ^V _{m + k} are the _{m + k} in the horizontal polarization state and the vertical polarization state, respectively. The symbol information of the pulse of the time is represented, A ^H _{n + k} and A ^V _{n + k} represent the symbol information of the pulse of the n + k time in the horizontal polarization state and the vertical polarization state, respectively, and (A ^H _{m + n + k} ) ^* and (A ^V _{m + n + k} ^* Represents the conjugate of the symbol information of the pulse at the m + n + k time in the horizontal polarization state and the vertical polarization state, respectively.

In another embodiment, when the input pulse signal is a dual polarization signal, the amount of perturbation is combined based on the weighting coefficient in step 303, and specifically, the following equation can be used.

Where Δ ^H _k and Δ ^V _k represent the sum of weighted values of the horizontal polarization state and the vertical polarization state of some terms at the k-th time, respectively, and C (m, n, z = L) is the transmission line Represents the weighting coefficient of each term at point L, m and n are integers, a = m × n and not 0, and A ^H _{m + k} and A ^V _{m + k} are the _{m + k} in the horizontal polarization state and the vertical polarization state, respectively. The symbol information of the pulse of the time is represented, A ^H _{n + k} and A ^V _{n + k} represent the symbol information of the pulse of the n + k time in the horizontal polarization state and the vertical polarization state, respectively, and (A ^H _{m + n + k} ) ^* and (A ^V _{m + n + k} ^* Represents the conjugate of the symbol information of the pulse at the m + n + k time in the horizontal polarization state and the vertical polarization state, respectively.

In another embodiment, when the input pulse signal is a single polarization signal, the term of perturbation amount is combined based on the weighting coefficient in step 303, and specifically, the following equation can be used.

In the equation, Δ _k represents the sum of the weight values of some terms at the k-th time, C (m, n, z = L) represents the weighting coefficient of each term at the transmission line L point, and m and n are integers. Yes, a = m × n and not 0, A _{m + k} and A _{n + k} represent the symbol information of the pulse at the m + k time and the n + k time, respectively, and (A _{m + n + k} ) ^* is the conjugate of the symbol information of the pulse at the m + n + k time. Represents.

In another embodiment, when the input pulse signal is a single polarization signal, the term of perturbation amount is combined based on the weighting coefficient in step 303, and specifically, the following equation can be used.

In the equation, Δ _k represents the sum of the weight values of some terms at the k-th time, C (m, n, z = L) represents the weighting coefficient of each term at the transmission line L point, and m and n are integers. Yes, a = m × n and not 0, A _{m + k} and A _{n + k} represent the symbol information of the pulse at the m + k time and the n + k time, respectively, and (A _{m + n + k} ) ^* is the conjugate of the symbol information of the pulse at the m + n + k time. Represents.

  FIG. 4 is another flowchart of the nonlinear compensation method of the embodiment of the present invention. As shown in FIG. 4, in the nonlinear compensation method, in step 401, the symbol information sequence of the pulse signal input at the transmission end is acquired, and the current time is determined by the weighting coefficient corresponding to each term acquired in advance. Calculating a weighted sum of pulse interaction terms at one or more times with respect to, obtaining a perturbation amount generated in a transmission path of a certain length, quantizing a weighting factor 403, and perturbing based on the weighting factor Step 404 for combining the terms of the quantities and converting the addition of complex numbers into a combination of symbol addition and multiplication in a finite symbol set, calculating the difference between the symbol information sequence and the processed perturbation quantity to compensate The symbol information sequence is acquired, and the transmitting end transmits a signal based on the compensated symbol information sequence. Including the flop 405.

In one embodiment, when the input pulse signal is a dual polarization signal, the perturbation amount term is combined based on the weighting coefficient in step 404, and specifically, the following equation can be used.

Where Δ ^H _k and Δ ^V _k represent the sum of weighted values of the horizontal polarization state and the vertical polarization state of some terms at the k-th time, respectively, and C (m, n, z = L) is the transmission line Represents the weighting coefficient of each term at point L, m and n are integers, Rp and Iq represent the real part and imaginary part of the coefficient C after quantization (mn ≠ 0, z = L), respectively, Ds Represents the imaginary part of the quantized coefficient C (m, n = 0, z = L), p, q, s represent different quantization series, and A ^H _{m + k} and A ^V _{m + k} are respectively horizontally polarized states. And A ^H _{n + k} and A ^V _{n + k} represent the symbol information of the pulse at the n + k time in the horizontal polarization state and the vertical polarization state, respectively, and (A ^H _{m + n +} ^{k) *} and _{^{(A V m + n + k}} ) * each horizontal Represents the conjugation of the symbol information of the pulses of the m + n + k time in the wave state and the vertical polarization state.

In another embodiment, when the input pulse signal is a single polarization signal, the term of perturbation amount is combined based on the weighting coefficient in step 404, and specifically, the following equation can be used.

Wherein, delta _k represents the sum of the weighted values of some sections of the k time, C (m, n, z = L) represents a weighting coefficient of each term in the transmission path L points, Rp and Iq, respectively quantum Represents the real and imaginary parts of the coefficient C after conversion (mn ≠ 0, z = L), m and n are integers, p and q represent different quantization series, and A _{m + k} and A _{n + k} are respectively Symbol information of the pulse at the ( _{m + k} ) time and the ( _{n + k} ) time is represented, and (A _{m + n + k} ) ^* represents the conjugate of the symbol information of the pulse at the ( _{m + n + k} ) time.

  In this embodiment, after step 404, the obtained perturbation amount is used to rotate by a predetermined phase, and the perturbation amount is adjusted by a predetermined width coefficient to further improve the system performance effectively. Can do.

  This embodiment further provides a transmitter. FIG. 5 is a diagram showing the configuration of the transmitter according to the embodiment of the present invention. As shown in FIG. 5, the transmitter includes a nonlinear compensator 501, a pulse shaper 502 and a signal transmitter 503.

  Here, the non-linear compensator 501 can compensate the symbol information sequence of the input pulse, and the non-linear compensator of the above embodiment can be used, which is not described here.

  The pulse shaper 502 is used to obtain the waveform of each pulse by performing pulse shaping based on the compensated symbol information sequence acquired by the nonlinear compensator 501.

  The signal transmitter 503 receives the waveform of each pulse transmitted by the pulse shaper 502 and is used to transmit the waveform after modulation.

  In this embodiment, a nonlinear compensator is applied in a transmitter, which can be applied in any optical communication system, including a system with electronic chromatic dispersion precompensation. Thereby, the transmitter may further include a chromatic dispersion compensation unit (not shown), and in a system including chromatic dispersion precompensation, an intra-channel nonlinear precompensator may be placed in front of the chromatic dispersion precompensation unit. . The weighting factor corresponding to the weighting value of the interaction of pulses at different times can still be calculated according to the above embodiment, and only the chromatic dispersion arrangement needs to consider the chromatic dispersion compensation module.

  As can be seen from the above embodiments, the nonlinear compensation device can compensate the symbol information of the pulse signal input at the transmission end, and when the device is applied to a transmitter, the transmitter can perform symbol information after the compensation. Can be used to perform pulse shaping and modulation, and finally transmit signals, and after these signals are subjected to the nonlinear effects of the optical fiber transmission line, the desired lossless signal can be obtained at the receiver.

  Also, depending on the characteristics of the weighting factor, the pulse action terms are combined, and complex addition is converted into a combination of symbol addition and multiplication within a finite symbol set, thereby further reducing the computational complexity and The demand can be relaxed.

  The above apparatus and method of the present embodiment can be realized by hardware, and can also be realized by linking software to hardware. The present embodiment relates to such a computer-readable program. When the program is executed by a logic unit, the logic component realizes the above-described apparatus or component, or the logic component causes the above-described various methods. Or a step can be realized. The present embodiment further relates to a storage medium such as a hard disk, a magnetic disk, an optical disk, a DVD, or a flash memory used for storing the above program.

  Although the present invention has been described above in connection with specific embodiments, those skilled in the art should understand that these descriptions are all illustrative and are not limitations on the protection scope of the present invention. is there. Those skilled in the art can make various variations and modifications to the present embodiment based on the spirit and principle of the present invention, and these variations and modifications are also within the scope of the present invention.

式中、Δ^Ｈ _ｋ及びΔ^Ｖ _ｋはそれぞれ第ｋ時刻の若干項の水平偏波状態と垂直偏波状態との重み付け値の和を表し、Ｃ（ｍ，ｎ，ｚ＝Ｌ）は伝送路Ｌ点における各項の重み付け係数を表し、ｍ及びｎは整数であり、ａ＝ｍ×ｎ且つ０ではなく、Ａ^Ｈ _ｍ＋ｋ及びＡ^Ｖ _ｍ＋ｋはそれぞれ水平偏波状態及び垂直偏波状態における第ｍ＋ｋ時刻のパルスのシンボル情報を表し、Ａ^Ｈ _ｎ＋ｋ及びＡ^Ｖ _ｎ＋ｋはそれぞれ水平偏波状態及び垂直偏波状態における第ｎ＋ｋ時刻のパルスのシンボル情報を表し、（Ａ^Ｈ _{ｍ＋ｎ＋ｋ}）^＊及び（Ａ^Ｖ _{ｍ＋ｎ＋ｋ}）^＊はそれぞれ水平偏波状態及び垂直偏波状態における第ｍ＋ｎ＋ｋ時刻のパルスのシンボル情報の共役を表す。
（付記４）
前記入力されたパルス信号は二重偏波信号であり、前記摂動量処理器が下記式で前記摂動量の項を結合する、付記２に記載の非線形補償装置：

式中、Δ^Ｈ _ｋ及びΔ^Ｖ _ｋはそれぞれ第ｋ時刻の若干項の水平偏波状態と垂直偏波状態との重み付け値の和を表し、Ｃ（ｍ，ｎ，ｚ＝Ｌ）は伝送路Ｌ点における各項の重み付け係数を表し、ｍ及びｎは整数であり、ａ＝ｍ×ｎ且つ０ではなく、Ａ^Ｈ _ｍ＋ｋ及びＡ^Ｖ _ｍ＋ｋはそれぞれ水平偏波状態及び垂直偏波状態における第ｍ＋ｋ時刻のパルスのシンボル情報を表し、Ａ^Ｈ _ｎ＋ｋ及びＡ^Ｖ _ｎ＋ｋはそれぞれ水平偏波状態及び垂直偏波状態における第ｎ＋ｋ時刻のパルスのシンボル情報を表し、（Ａ^Ｈ _{ｍ＋ｎ＋ｋ}）^＊及び（Ａ^Ｖ _{ｍ＋ｎ＋ｋ}）^＊はそれぞれ水平偏波状態及び垂直偏波状態における第ｍ＋ｎ＋ｋ時刻のパルスのシンボル情報の共役を表す。
（付記５）
前記入力されたパルス信号は単偏波信号であり、前記摂動量処理器が下記式で前記摂動量の項を結合する、付記２に記載の非線形補償装置。

式中、Δ_ｋは第ｋ時刻の若干項の重み付け値の和を表し、Ｃ（ｍ，ｎ，ｚ＝Ｌ）は伝送路Ｌ点における各項の重み付け係数を表し、ｍ及びｎは整数であり、ａ＝ｍ×ｎ且つ0ではなく、Ａ_ｍ＋ｋ、Ａ_ｎ＋ｋはそれぞれ第ｍ＋ｋ時刻、第ｎ＋ｋ時刻のパルスのシンボル情報を表し、（Ａ_{ｍ＋ｎ＋ｋ}）^＊は第ｍ＋ｎ＋ｋ時刻のパルスのシンボル情報の共役を表す。
（付記６）
前記入力されたパルス信号は単偏波信号であり、前記摂動量処理器が下記式で前記摂動量の項を結合する、付記２に記載の非線形補償装置。

式中、Δ_ｋは第ｋ時刻の若干項の重み付け値の和を表し、Ｃ（ｍ，ｎ，ｚ＝Ｌ）は伝送路Ｌ点における各項の重み付け係数を表し、ｍ及びｎは整数であり、ａ＝ｍ×ｎ且つ０ではなく、Ａ_ｍ＋ｋ、Ａ_ｎ＋ｋはそれぞれ第ｍ＋ｋ時刻、第ｎ＋ｋ時刻のパルスのシンボル情報を表し、（Ａ_{ｍ＋ｎ＋ｋ}）^＊は第ｍ＋ｎ＋ｋ時刻のパルスのシンボル情報の共役を表す。
（付記７）
前記摂動量処理器は前記重み付け係数に対応する項を結合する前に、さらに前記重み付け係数を量子化する、付記２に記載の非線形補償装置。
（付記８）
前記入力されたパルス信号は二重偏波信号であり、前記摂動量処理器が下記式で前記摂動量の項を結合する、付記７に記載の非線形補償装置：

式中、Δ^Ｈ _ｋ及びΔ^Ｖ _ｋはそれぞれ第ｋ時刻の若干項の水平偏波状態と垂直偏波状態との重み付け値の和を表し、Ｃ（ｍ，ｎ，ｚ＝Ｌ）は伝送路Ｌ点における各項の重み付け係数を表し、ｍ及びｎは整数であり、Ｒｐ及びＩｑはそれぞれ量子化後の係数Ｃ（ｍｎ≠０，ｚ＝Ｌ）の実部及び虚部を表し、Ｄｓは量子化後の係数Ｃ（ｍ，ｎ＝０，ｚ＝Ｌ）の虚部を表し、ｐ，ｑ，ｓはそれぞれ異なる量子化級数を表し、Ａ^Ｈ _ｍ＋ｋ及びＡ^Ｖ _ｍ＋ｋはそれぞれ水平偏波状態及び垂直偏波状態における第ｍ＋ｋ時刻のパルスのシンボル情報を表し、Ａ^Ｈ _ｎ＋ｋ及びＡ^Ｖ _ｎ＋ｋはそれぞれ水平偏波状態及び垂直偏波状態における第ｎ＋ｋ時刻のパルスのシンボル情報を表し、（Ａ^Ｈ _{ｍ＋ｎ＋ｋ}）^＊及び（Ａ^Ｖ _{ｍ＋ｎ＋ｋ}）^＊はそれぞれ水平偏波状態及び垂直偏波状態における第ｍ＋ｎ＋ｋ時刻のパルスのシンボル情報の共役を表す。
（付記９）
前記入力されたパルス信号は単偏波信号であり、前記摂動量処理器が下記式で前記摂動量の項を結合する、付記７に記載の非線形補償装置：

式中、Δ_ｋは第ｋ時刻の若干項の重み付け値の和を表し、Ｃ（ｍ，ｎ，ｚ＝Ｌ）は伝送路Ｌ点における各項の重み付け係数を表し、Ｒｐ及びＩｑはそれぞれ量子化後の係数Ｃ（ｍｎ≠０，ｚ＝Ｌ）の実部及び虚部を表し、ｍ及びｎは整数であり、ｐ，ｑはそれぞれ異なる量子化級数を表し、Ａ_ｍ＋ｋ、Ａ_ｎ＋ｋはそれぞれ第ｍ＋ｋ時刻、第ｎ＋ｋ時刻のパルスのシンボル情報を表し、（Ａ_{ｍ＋ｎ＋ｋ}）^＊は第ｍ＋ｎ＋ｋ時刻のパルスのシンボル情報の共役を表す。
（付記１０）
前記摂動量処理器はさらに取得した前記摂動量を所定の位相分回転し、所定の幅係数によって前記摂動量を調整するために用いられる、付記１または２に記載の非線形補償装置。
（付記１１）
送信端で入力されたパルス信号のシンボル情報シーケンスを取得し、
あらかじめ取得しておいた各項に対応する重み付け係数によって、現在時刻に対する１つ以上の時刻におけるパルス相互作用項の重み付け和を計算して一定の長さの伝送路において発生する摂動量を取得し、
前記重み付け係数に基づき前記摂動量の項を結合し、複素数の加法を有限シンボル集合内のシンボルの加法と乗法との組み合わせに変換させ、
前記シンボル情報シーケンスと処理を行った摂動量との差分を計算して補償後のシンボル情報シーケンスを取得して、送信端に前記補償後のシンボル情報シーケンスに基づき信号を送信させる
ことを含む、非線形補償方法。
（付記１２）
前記重み付け係数に基づき前記摂動量の項を結合し、具体的には、
同一または近似的同一の前記重み付け係数に対応する項を結合し、または、前記重み付け係数の実部に対応する項を結合し、または、前記重み付け係数の虚部に対応する項を結合することを含む、付記１１に記載の非線形補償方法。
（付記１３）
前記入力されたパルス信号は二重偏波信号であり、前記重み付け係数に基づき下記式で前記摂動量の項を結合する、付記１２に記載の非線形補償方法。

式中、Δ^Ｈ _ｋ及びΔ^Ｖ _ｋはそれぞれ第ｋ時刻の若干項の水平偏波状態と垂直偏波状態との重み付け値の和を表し、Ｃ（ｍ，ｎ，ｚ＝Ｌ）は伝送路Ｌ点における各項の重み付け係数を表し、ｍ及びｎは整数であり、ａ＝ｍ×ｎ且つ０ではなく、Ａ^Ｈ _ｍ＋ｋ及びＡ^Ｖ _ｍ＋ｋはそれぞれ水平偏波状態及び垂直偏波状態における第ｍ＋ｋ時刻のパルスのシンボル情報を表し、Ａ^Ｈ _ｎ＋ｋ及びＡ^Ｖ _ｎ＋ｋはそれぞれ水平偏波状態及び垂直偏波状態における第ｎ＋ｋ時刻のパルスのシンボル情報を表し、（Ａ^Ｈ _{ｍ＋ｎ＋ｋ}）^＊及び（Ａ^Ｖ _{ｍ＋ｎ＋ｋ}）^＊はそれぞれ水平偏波状態及び垂直偏波状態における第ｍ＋ｎ＋ｋ時刻のパルスのシンボル情報の共役を表す。
（付記１４）
前記入力されたパルス信号は二重偏波信号であり、前記重み付け係数に基づき下記式で前記摂動量の項を結合する、付記１２に記載の非線形補償方法。

式中、Δ^Ｈ _ｋ及びΔ^Ｖ _ｋはそれぞれ第ｋ時刻の若干項の水平偏波状態と垂直偏波状態との重み付け値の和を表し、Ｃ（ｍ，ｎ，ｚ＝Ｌ）は伝送路Ｌ点における各項の重み付け係数を表し、ｍ及びｎは整数であり、ａ＝ｍ×ｎ且つ０ではなく、Ａ^Ｈ _ｍ＋ｋ及びＡ^Ｖ _ｍ＋ｋはそれぞれ水平偏波状態及び垂直偏波状態における第ｍ＋ｋ時刻のパルスのシンボル情報を表し、Ａ^Ｈ _ｎ＋ｋ及びＡ^Ｖ _ｎ＋ｋはそれぞれ水平偏波状態及び垂直偏波状態における第ｎ＋ｋ時刻のパルスのシンボル情報を表し、（Ａ^Ｈ _{ｍ＋ｎ＋ｋ}）^＊及び（Ａ^Ｖ _{ｍ＋ｎ＋ｋ}）^＊はそれぞれ水平偏波状態及び垂直偏波状態における第ｍ＋ｎ＋ｋ時刻のパルスのシンボル情報の共役を表す。
（付記１５）
前記入力されたパルス信号は単偏波信号であり、前記重み付け係数に基づき下記式で前記摂動量の項を結合する、付記１２に記載の非線形補償方法。

式中、Δ_ｋは第ｋ時刻の若干項の重み付け値の和を表し、Ｃ（ｍ，ｎ，ｚ＝Ｌ）は伝送路Ｌ点における各項の重み付け係数を表し、ｍ及びｎは整数であり、ａ＝ｍ×ｎ且つ０ではなく、Ａ_ｍ＋ｋ、Ａ_ｎ＋ｋはそれぞれ第ｍ＋ｋ時刻、第ｎ＋ｋ時刻のパルスのシンボル情報を表し、（Ａ_{ｍ＋ｎ＋ｋ}）^＊は第ｍ＋ｎ＋ｋ時刻のパルスのシンボル情報の共役を表す。
（付記１６）
前記入力されたパルス信号は単偏波信号であり、前記重み付け係数に基づき下記式で前記摂動量の項を結合する、付記１２に記載の非線形補償方法。

式中、Δ_ｋは第ｋ時刻の若干項の重み付け値の和を表し、Ｃ（ｍ，ｎ，ｚ＝Ｌ）は伝送路Ｌ点における各項の重み付け係数を表し、ｍ及びｎは整数であり、ａ＝ｍ×ｎ且つ０ではなく、Ａ_ｍ＋ｋ、Ａ_ｎ＋ｋはそれぞれ第ｍ＋ｋ時刻、第ｎ＋ｋ時刻のパルスのシンボル情報を表し、（Ａ_{ｍ＋ｎ＋ｋ}）^＊は第ｍ＋ｎ＋ｋ時刻のパルスのシンボル情報の共役を表す。
（付記１７）
前記重み付け係数に基づき前記摂動量の項を結合する前に、前記重み付け係数を量子化することをさらに含む、付記１２に記載の非線形補償方法。
（付記１８）
前記入力されたパルス信号は二重偏波信号であり、前記重み付け係数に基づき下記式で前記摂動量の項を結合する、付記１７に記載の非線形補償方法。

式中、Δ^Ｈ _ｋ及びΔ^Ｖ _ｋはそれぞれ第ｋ時刻の若干項の水平偏波状態と垂直偏波状態との重み付け値の和を表し、Ｃ（ｍ，ｎ，ｚ＝Ｌ）は伝送路Ｌ点における各項の重み付け係数を表し、ｍ及びｎは整数であり、Ｒｐ及びＩｑはそれぞれ量子化後の係数Ｃ（ｍｎ≠０，ｚ＝Ｌ）の実部及び虚部を表し、Ｄｓは量子化後の係数Ｃ（ｍ，ｎ＝０，ｚ＝Ｌ）の虚部を表し、ｐ，ｑ，ｓはそれぞれ異なる量子化級数を表し、Ａ^Ｈ _ｍ＋ｋ及びＡ^Ｖ _ｍ＋ｋはそれぞれ水平偏波状態及び垂直偏波状態における第ｍ＋ｋ時刻のパルスのシンボル情報を表し、Ａ^Ｈ _ｎ＋ｋ及びＡ^Ｖ _ｎ＋ｋはそれぞれ水平偏波状態及び垂直偏波状態における第ｎ＋ｋ時刻のパルスのシンボル情報を表し、（Ａ^Ｈ _{ｍ＋ｎ＋ｋ}）^＊及び（Ａ^Ｖ _{ｍ＋ｎ＋ｋ}）^＊はそれぞれ水平偏波状態及び垂直偏波状態における第ｍ＋ｎ＋ｋ時刻のパルスのシンボル情報の共役を表す。
（付記１９）
前記入力されたパルス信号は単偏波信号であり、前記重み付け係数に基づき下記式で前記摂動量の項を結合する、付記１７に記載の非線形補償方法。

式中、Δ_ｋは第ｋ時刻の若干項の重み付け値の和を表し、Ｃ（ｍ，ｎ，ｚ＝Ｌ）は伝送路Ｌ点における各項の重み付け係数を表し、Ｒｐ及びＩｑはそれぞれ量子化後の係数Ｃ（ｍｎ≠０，ｚ＝Ｌ）の実部及び虚部を表し、ｍ及びｎは整数であり、ｐ，ｑはそれぞれ異なる量子化級数を表し、Ａ_ｍ＋ｋ、Ａ_ｎ＋ｋはそれぞれ第ｍ＋ｋ時刻、第ｎ＋ｋ時刻のパルスのシンボル情報を表し、（Ａ_{ｍ＋ｎ＋ｋ}）^＊は第ｍ＋ｎ＋ｋ時刻のパルスのシンボル情報の共役を表す。
（付記２０）
付記１ないし１０のいずれか１項に記載の非線形補償装置を含み、さらに、
前記非線形補償装置が取得した補償後のシンボル情報シーケンスに基づきパルス成型を行って各パルスの波形を取得するためのパルス成型器と、
前記パルス成型器が送信した各パルスの波形を受信し、前記波形を変調後に送信するための信号送信器と、
を含む送信機。 Regarding the embodiment including the above examples, the following additional notes are disclosed.
(Appendix 1)
An information sequence acquisition unit for acquiring a symbol information sequence of the pulse signal input at the transmission end;
Calculates the weighted sum of pulse interaction terms at one or more times with respect to the current time by using the weighting coefficient corresponding to each term acquired in advance, and calculates the amount of perturbation generated in a transmission line of a certain length. A perturbation amount acquirer for
A perturbation amount processor that combines the perturbation amount terms based on the weighting factors to convert the addition of complex numbers into a combination of addition and multiplication of symbols in a finite symbol set;
An information compensator for calculating a difference between the symbol information sequence and a processed perturbation amount to obtain a compensated symbol information sequence and causing a transmission end to transmit a signal based on the compensated symbol information sequence When,
A non-linear compensator comprising:
(Appendix 2)
Specifically, the perturbation amount processor combines terms corresponding to the same or approximately the same weighting factor, or combines terms corresponding to the real part of the weighting factor, or of the weighting factor. The nonlinear compensator according to appendix 1, which can be used to combine terms corresponding to imaginary parts.
(Appendix 3)
The nonlinear compensator according to appendix 2, wherein the input pulse signal is a dual polarization signal, and the perturbation amount processor combines the terms of the perturbation amount by the following equation.

Where Δ ^H _k and Δ ^V _k represent the sum of weighted values of the horizontal polarization state and the vertical polarization state of some terms at the k-th time, respectively, and C (m, n, z = L) is the transmission line Represents the weighting coefficient of each term at point L, m and n are integers, a = m × n and not 0, and A ^H _{m + k} and A ^V _{m + k} are the _{m + k} in the horizontal polarization state and the vertical polarization state, respectively. The symbol information of the pulse of the time is represented, A ^H _{n + k} and A ^V _{n + k} represent the symbol information of the pulse of the n + k time in the horizontal polarization state and the vertical polarization state, respectively, and (A ^H _{m + n + k} ) ^* and (A ^V _{m + n + k} ^* Represents the conjugate of the symbol information of the pulse at the m + n + k time in the horizontal polarization state and the vertical polarization state, respectively.
(Appendix 4)
The nonlinear compensator according to appendix 2, wherein the input pulse signal is a dual polarization signal, and the perturbation amount processor combines the perturbation amount terms by the following equation:

Where Δ ^H _k and Δ ^V _k represent the sum of weighted values of the horizontal polarization state and the vertical polarization state of some terms at the k-th time, respectively, and C (m, n, z = L) is the transmission line Represents the weighting coefficient of each term at point L, m and n are integers, a = m × n and not 0, and A ^H _{m + k} and A ^V _{m + k} are the _{m + k} in the horizontal polarization state and the vertical polarization state, respectively. The symbol information of the pulse of the time is represented, A ^H _{n + k} and A ^V _{n + k} represent the symbol information of the pulse of the n + k time in the horizontal polarization state and the vertical polarization state, respectively, and (A ^H _{m + n + k} ) ^* and (A ^V _{m + n + k} ^* Represents the conjugate of the symbol information of the pulse at the m + n + k time in the horizontal polarization state and the vertical polarization state, respectively.
(Appendix 5)
The nonlinear compensator according to appendix 2, wherein the input pulse signal is a single polarization signal, and the perturbation amount processor combines the terms of the perturbation amount by the following equation.

In the equation, Δ _k represents the sum of the weight values of some terms at the k-th time, C (m, n, z = L) represents the weighting coefficient of each term at the transmission line L point, and m and n are integers. Yes, a = m × n and not 0, A _{m + k} and A _{n + k} represent the symbol information of the pulse at the m + k time and the n + k time, respectively, and (A _{m + n + k} ) ^* is the conjugate of the symbol information of the pulse at the m + n + k time. Represents.
(Appendix 6)
The nonlinear compensator according to appendix 2, wherein the input pulse signal is a single polarization signal, and the perturbation amount processor combines the terms of the perturbation amount by the following equation.

In the equation, Δ _k represents the sum of the weight values of some terms at the k-th time, C (m, n, z = L) represents the weighting coefficient of each term at the transmission line L point, and m and n are integers. Yes, a = m × n and not 0, A _{m + k} and A _{n + k} represent the symbol information of the pulse at the m + k time and the n + k time, respectively, and (A _{m + n + k} ) ^* is the conjugate of the symbol information of the pulse at the m + n + k time. Represents.
(Appendix 7)
The nonlinear compensator according to appendix 2, wherein the perturbation amount processor further quantizes the weighting coefficient before combining the terms corresponding to the weighting coefficient.
(Appendix 8)
The nonlinear compensator according to appendix 7, wherein the input pulse signal is a dual polarization signal, and the perturbation amount processor combines the perturbation amount terms by the following formula:

Where Δ ^H _k and Δ ^V _k represent the sum of weighted values of the horizontal polarization state and the vertical polarization state of some terms at the k-th time, respectively, and C (m, n, z = L) is the transmission line Represents the weighting coefficient of each term at point L, m and n are integers, Rp and Iq represent the real part and imaginary part of the coefficient C after quantization (mn ≠ 0, z = L), respectively, Ds Represents the imaginary part of the quantized coefficient C (m, n = 0, z = L), p, q, s represent different quantization series, and A ^H _{m + k} and A ^V _{m + k} are respectively horizontally polarized states. And A ^H _{n + k} and A ^V _{n + k} represent the symbol information of the pulse at the n + k time in the horizontal polarization state and the vertical polarization state, respectively, and (A ^H _{m + n +} ^{k) *} and _{^{(A V m + n + k}} ) * each horizontal Represents the conjugation of the symbol information of the pulses of the m + n + k time in the wave state and the vertical polarization state.
(Appendix 9)
The nonlinear compensator according to appendix 7, wherein the input pulse signal is a single polarization signal, and the perturbation amount processor combines the terms of the perturbation amount with the following equation:

Wherein, delta _k represents the sum of the weighted values of some sections of the k time, C (m, n, z = L) represents a weighting coefficient of each term in the transmission path L points, Rp and Iq, respectively quantum Represents the real and imaginary parts of the coefficient C after conversion (mn ≠ 0, z = L), m and n are integers, p and q represent different quantization series, and A _{m + k} and A _{n + k} are respectively Symbol information of the pulse at the ( _{m + k} ) time and the ( _{n + k} ) time is represented, and (A _{m + n + k} ) ^* represents the conjugate of the symbol information of the pulse at the ( _{m + n + k} ) time.
(Appendix 10)
The nonlinear compensator according to appendix 1 or 2, wherein the perturbation amount processor further rotates the acquired perturbation amount by a predetermined phase, and is used to adjust the perturbation amount by a predetermined width coefficient.
(Appendix 11)
Obtain the symbol information sequence of the pulse signal input at the transmission end,
The weighting coefficient corresponding to each term acquired in advance is used to calculate the weighted sum of the pulse interaction terms at one or more times with respect to the current time to obtain the amount of perturbation that occurs in the transmission line of a certain length. ,
Combining the perturbation quantity terms based on the weighting factors to convert complex addition to a combination of symbol addition and multiplication in a finite symbol set;
Calculating a difference between the symbol information sequence and the amount of perturbation that has been processed to obtain a compensated symbol information sequence, and causing a transmission end to transmit a signal based on the compensated symbol information sequence. Compensation method.
(Appendix 12)
Combining the perturbation terms based on the weighting factor, specifically:
Combining terms corresponding to the same or approximately the same weighting factor, combining terms corresponding to the real part of the weighting factor, or combining terms corresponding to the imaginary part of the weighting factor. The nonlinear compensation method according to appendix 11, including:
(Appendix 13)
13. The nonlinear compensation method according to appendix 12, wherein the input pulse signal is a dual polarization signal, and the perturbation amount term is combined by the following equation based on the weighting coefficient.

Where Δ ^H _k and Δ ^V _k represent the sum of weighted values of the horizontal polarization state and the vertical polarization state of some terms at the k-th time, respectively, and C (m, n, z = L) is the transmission line Represents the weighting coefficient of each term at point L, m and n are integers, a = m × n and not 0, and A ^H _{m + k} and A ^V _{m + k} are the _{m + k} in the horizontal polarization state and the vertical polarization state, respectively. The symbol information of the pulse of the time is represented, A ^H _{n + k} and A ^V _{n + k} represent the symbol information of the pulse of the n + k time in the horizontal polarization state and the vertical polarization state, respectively, and (A ^H _{m + n + k} ) ^* and (A ^V _{m + n + k} ^* Represents the conjugate of the symbol information of the pulse at the m + n + k time in the horizontal polarization state and the vertical polarization state, respectively.
(Appendix 14)
13. The nonlinear compensation method according to appendix 12, wherein the input pulse signal is a dual polarization signal, and the perturbation amount term is combined by the following equation based on the weighting coefficient.

Where Δ ^H _k and Δ ^V _k represent the sum of weighted values of the horizontal polarization state and the vertical polarization state of some terms at the k-th time, respectively, and C (m, n, z = L) is the transmission line Represents the weighting coefficient of each term at point L, m and n are integers, a = m × n and not 0, and A ^H _{m + k} and A ^V _{m + k} are the _{m + k} in the horizontal polarization state and the vertical polarization state, respectively. The symbol information of the pulse of the time is represented, A ^H _{n + k} and A ^V _{n + k} represent the symbol information of the pulse of the n + k time in the horizontal polarization state and the vertical polarization state, respectively, and (A ^H _{m + n + k} ) ^* and (A ^V _{m + n + k} ^* Represents the conjugate of the symbol information of the pulse at the m + n + k time in the horizontal polarization state and the vertical polarization state, respectively.
(Appendix 15)
13. The nonlinear compensation method according to appendix 12, wherein the input pulse signal is a single polarization signal, and the perturbation amount term is combined by the following equation based on the weighting coefficient.

In the equation, Δ _k represents the sum of the weight values of some terms at the k-th time, C (m, n, z = L) represents the weighting coefficient of each term at the transmission line L point, and m and n are integers. Yes, a = m × n and not 0, A _{m + k} and A _{n + k} represent the symbol information of the pulse at the m + k time and the n + k time, respectively, and (A _{m + n + k} ) ^* is the conjugate of the symbol information of the pulse at the m + n + k time. Represents.
(Appendix 16)
13. The nonlinear compensation method according to appendix 12, wherein the input pulse signal is a single polarization signal, and the perturbation amount term is combined by the following equation based on the weighting coefficient.

In the equation, Δ _k represents the sum of the weight values of some terms at the k-th time, C (m, n, z = L) represents the weighting coefficient of each term at the transmission line L point, and m and n are integers. Yes, a = m × n and not 0, A _{m + k} and A _{n + k} represent the symbol information of the pulse at the m + k time and the n + k time, respectively, and (A _{m + n + k} ) ^* is the conjugate of the symbol information of the pulse at the m + n + k time. Represents.
(Appendix 17)
The nonlinear compensation method according to claim 12, further comprising quantizing the weighting coefficient before combining the perturbation amount terms based on the weighting coefficient.
(Appendix 18)
18. The nonlinear compensation method according to appendix 17, wherein the input pulse signal is a dual polarization signal, and the perturbation amount term is combined by the following equation based on the weighting coefficient.

Where Δ ^H _k and Δ ^V _k represent the sum of weighted values of the horizontal polarization state and the vertical polarization state of some terms at the k-th time, respectively, and C (m, n, z = L) is the transmission line Represents the weighting coefficient of each term at point L, m and n are integers, Rp and Iq represent the real part and imaginary part of the coefficient C after quantization (mn ≠ 0, z = L), respectively, Ds Represents the imaginary part of the quantized coefficient C (m, n = 0, z = L), p, q, s represent different quantization series, and A ^H _{m + k} and A ^V _{m + k} are respectively horizontally polarized states. And A ^H _{n + k} and A ^V _{n + k} represent the symbol information of the pulse at the n + k time in the horizontal polarization state and the vertical polarization state, respectively, and (A ^H _{m + n +} ^{k) *} and _{^{(A V m + n + k}} ) * each horizontal Represents the conjugation of the symbol information of the pulses of the m + n + k time in the wave state and the vertical polarization state.
(Appendix 19)
18. The nonlinear compensation method according to appendix 17, wherein the input pulse signal is a single polarization signal, and the perturbation amount term is combined by the following equation based on the weighting coefficient.

Wherein, delta _k represents the sum of the weighted values of some sections of the k time, C (m, n, z = L) represents a weighting coefficient of each term in the transmission path L points, Rp and Iq, respectively quantum Represents the real and imaginary parts of the coefficient C after conversion (mn ≠ 0, z = L), m and n are integers, p and q represent different quantization series, and A _{m + k} and A _{n + k} are respectively Symbol information of the pulse at the ( _{m + k} ) time and the ( _{n + k} ) time is represented, and (A _{m + n + k} ) ^* represents the conjugate of the symbol information of the pulse at the ( _{m + n + k} ) time.
(Appendix 20)
Including the nonlinear compensator according to any one of appendices 1 to 10, and
A pulse shaper for obtaining a waveform of each pulse by performing pulse shaping based on a symbol information sequence after compensation obtained by the nonlinear compensation device;
A signal transmitter for receiving the waveform of each pulse transmitted by the pulse shaper and transmitting the waveform after modulating the waveform;
Including transmitter.

Claims (6)

An information sequence acquisition unit for acquiring a symbol information sequence of the pulse signal input at the transmission end;
A weighting coefficient corresponding to each term acquired in advance is used to calculate a weighted sum of pulse interaction terms at one or more times with respect to the current time, thereby acquiring a perturbation amount generated in a transmission line of a certain length. A perturbation amount acquirer for
A perturbation amount processor that combines the perturbation amount terms based on the weighting factors to convert the addition of complex numbers into a combination of addition and multiplication of symbols in a finite symbol set;
An information compensator for calculating a difference between the symbol information sequence and a processed perturbation amount to obtain a compensated symbol information sequence and causing a transmission end to transmit a signal based on the compensated symbol information sequence When,
Including
The perturbation amount processor combines terms corresponding to the same or approximately the same weighting coefficient, combines terms corresponding to the real part of the weighting coefficient, or corresponds to an imaginary part of the weighting coefficient. Used to combine terms
The perturbation amount processor further quantizes the weighting factor before combining the terms corresponding to the weighting factor,
The input pulse signal is a dual polarization signal, and the perturbation amount processor combines the perturbation amount terms by the following equation:

Where Δ ^H _k and Δ ^V _k represent the sum of weighted values of the horizontal polarization state and the vertical polarization state of some terms at the k-th time, respectively, and C (m, n, z = L) is the transmission line Represents the weighting coefficient of each term at point L, m and n are integers, R _p and I _q represent the real part and the imaginary part of the quantized coefficient C (mn ≠ 0, z = L), respectively; D _s represents the imaginary part of C (m, 0, z = L) after quantization, p, q, s represent different quantization series, and A ^H _{m + k} and A ^V _{m + k} are respectively horizontally polarized states. And A ^H _{n + k} and A ^V _{n + k} represent the symbol information of the pulse at the n + k time in the horizontal polarization state and the vertical polarization state, respectively, and (A ^H _{m + n + k} ) ^* and (A ^V _{m + n + k} ) ^* are horizontal polarization states, respectively. And the conjugate of the symbol information of the pulse at the m + n + k time in the vertical polarization state .
Nonlinear compensator. An information sequence acquisition unit for acquiring a symbol information sequence of the pulse signal input at the transmission end;
A weighting coefficient corresponding to each term acquired in advance is used to calculate a weighted sum of pulse interaction terms at one or more times with respect to the current time, thereby acquiring a perturbation amount generated in a transmission line of a certain length. A perturbation amount acquirer for
A perturbation amount processor that combines the perturbation amount terms based on the weighting factors to convert the addition of complex numbers into a combination of addition and multiplication of symbols in a finite symbol set;
An information compensator for calculating a difference between the symbol information sequence and a processed perturbation amount to obtain a compensated symbol information sequence and causing a transmission end to transmit a signal based on the compensated symbol information sequence When,
Including
The perturbation amount processor combines terms corresponding to the same or approximately the same weighting coefficient, combines terms corresponding to the real part of the weighting coefficient, or corresponds to an imaginary part of the weighting coefficient. Used to combine terms
The perturbation amount processor further quantizes the weighting factor before combining the terms corresponding to the weighting factor,
The input pulse signal is a single polarization signal, and the perturbation amount processor combines the perturbation amounts by the following equation:

In the equation, Δ _k represents the sum of the weight values of some terms at the k-th time, C (m, n, z = L) represents the weight coefficient of each term at the transmission line L point, and R _p and I _q are Each represents a real part and an imaginary part of the coefficient C after quantization (mn ≠ 0, z = L), m and n are integers, p and q represent different quantization series, A _{m + k} , A _{n + k} Represents the symbol information of the pulse at the ( _{m + k} ) _th time and the ( _{n + k} ) th time, respectively, ( _{Am + n + k} ) ^* represents the conjugate of the symbol information of the pulse at the ( _{m + n + k} ) th time ,
Nonlinear compensator.   The non-linear compensation apparatus according to claim 1, wherein the perturbation amount processor further rotates the acquired perturbation amount by a predetermined phase and adjusts the perturbation amount by a predetermined width coefficient. A non-linear compensation device according to any one of claims 1 to 3 , further comprising:
A pulse shaper for obtaining a waveform of each pulse by performing pulse shaping based on a symbol information sequence after compensation obtained by the nonlinear compensation device;
A signal transmitter for receiving the waveform of each pulse transmitted by the pulse shaper and transmitting the waveform after modulating the waveform;
Including transmitter . Obtain the symbol information sequence of the pulse signal input at the transmission end,
The weighting coefficient corresponding to each term acquired in advance is used to calculate the weighted sum of the pulse interaction terms at one or more times with respect to the current time to obtain the amount of perturbation that occurs in the transmission line of a certain length. ,
Combining the perturbation quantity terms based on the weighting factors to convert complex addition to a combination of symbol addition and multiplication in a finite symbol set;
Calculating a difference between the symbol information sequence and the amount of perturbation that has been processed to obtain a compensated symbol information sequence, and causing a transmission end to transmit a signal based on the compensated symbol information sequence;
In combining the perturbation amount terms based on the weighting factors, combining terms corresponding to the same or approximately the same weighting factors, combining terms corresponding to the real part of the weighting factors, or Combining terms corresponding to the imaginary part of the weighting factor;
Prior to combining terms corresponding to the weighting factors, the weighting factors are further quantized,
The input pulse signal is a dual polarization signal, and in the combination of the perturbation amount terms, the perturbation amount terms are combined by the following equation:

Where Δ ^H _k And Δ ^V _k Represents the sum of the weighted values of the horizontal polarization state and the vertical polarization state of some terms at time k, and C (m, n, z = L) represents the weighting coefficient of each term at the transmission line L point. , M and n are integers and R _p And I _q  Represents the real part and the imaginary part of the coefficient C after quantization (mn ≠ 0, z = L), and D _s  Represents the imaginary part of C (m, 0, z = L) after quantization, p, q, s represent different quantization series, and A ^H _{m + k} And A ^V _{m + k} Represents symbol information of the pulse at the (m + k) th time in the horizontal polarization state and the vertical polarization state, respectively. ^H _{n + k} And A ^V _{n + k} Represents symbol information of the pulse at the (n + k) th time in the horizontal polarization state and the vertical polarization state, respectively (A ^H _{m + n + k} ) ^* And (A ^V _{m + n + k} ) ^* Represents the conjugate of the symbol information of the pulse at the m + n + k time in the horizontal polarization state and the vertical polarization state, respectively.
Nonlinear compensation method. Obtain the symbol information sequence of the pulse signal input at the transmission end,
The weighting coefficient corresponding to each term acquired in advance is used to calculate the weighted sum of the pulse interaction terms at one or more times with respect to the current time to obtain the amount of perturbation that occurs in the transmission line of a certain length. ,
Combining the perturbation quantity terms based on the weighting factors to convert complex addition to a combination of symbol addition and multiplication in a finite symbol set;
Calculating a difference between the symbol information sequence and the amount of perturbation that has been processed to obtain a compensated symbol information sequence, and causing a transmission end to transmit a signal based on the compensated symbol information sequence;
In combining the perturbation amount terms based on the weighting factors, combining terms corresponding to the same or approximately the same weighting factors, combining terms corresponding to the real part of the weighting factors, or Combining terms corresponding to the imaginary part of the weighting factor;
Prior to combining terms corresponding to the weighting factors, the weighting factors are further quantized,
The input pulse signal is a single polarization signal, and in the combination of the perturbation amount terms, the perturbation amount is combined by the following equation:

Where Δ _k Represents the sum of the weight values of some terms at the k-th time, C (m, n, z = L) represents the weight coefficient of each term at the transmission line L point, and R _p And I _q  Represents the real part and the imaginary part of the quantized coefficient C (mn ≠ 0, z = L), m and n are integers, p and q represent different quantization series, and A _{m + k} , A _{n + k} Represents symbol information of the pulses at the (m + k) th time and the (n + k) th time, respectively (A _{m + n + k} ) ^* Represents the conjugate of the symbol information of the pulse at the m + n + k time,
Nonlinear compensation method.

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